Dispersions of benzimidazolylstilbene whitening and brightening agents and production thereof



Un ed S tes DISPERSIONS F BENZIMIDAZOLYLSTEBENE WHITENING ANDBRIGHTENING AGENTS AND PRODUCTION THEREOF Nathan N. Crounse, Cincinnati,Ohio, assignor to Sterling Drug Inc., New York, N. a corporation ofDelaware No Drawing. Filed May 11, 1959, Ser. No. 812,121

Claims. (Cl. 252-152) This invention relates to the production ofcompositions comprising certain water-insoluble benzimidazolylstilbenewhitening and brightening 7 agents and higher fatty acid amides oralkanolamides, to the compositions thus obtained, and to the use of saidcompositions in the preparation of detergent compositions havingwhitening and brightening properties. I The incorporation of relativelysmall amounts of fluorescent whitening and brightening agents intowatersolublesynthetic organic anionic detergents intended for use inlaundering is now a common practice. This procedure is of course quitesimple when whitening and brightening agents have suitablewater-solubility are em ployed, since conventional mixing and dispersingprocedures of the detergent art readily afford homogeneous aqueouscompositions, which if desired can be dried in the usual fashion, as byspray-drying. However, when substantially water-insoluble fluorescentwhitening and brightening agents are involved, there arises the problemof obtaining uniform and satisfactory dispersion of the relatively smallquantity of the fluorescent agent in the detergent as reflected intherecovery of the full dyeing. strength. While it is frequently possibleto dissolve the water-insoluble fluorescent agent in one of the usualliquid organic solvents, such as an a alcohol, ketone, or hydrocarbon,and thus facilitate its uniform incorporation into the detergent,toxicity and explosion hazards may be encountered with such solvents.Moreover, because of handling problems, some detergent manufacturersprefer not to receive the Whitening and brightening agent in the form ofa liquid prepartion, preferring instead to receive and handle solidmaterials. ,In- Crounse US. Patent 2,838,5 0,4,'issued June 10, 1958,there are described benzimidazolylstilbene whitening andbn'ghteningagents, certain of which have the structural formula ii example methyl,ethyl, n-propyl, isobutylg'a'nd n-hexyl;

1 hydroxyl-lower alkyl containing 2-6 carbon at'oms, for

example Z-hydroxyethyl and 2,3-dihydroxypropyl; 2-hydroxy-B-sulfopropyl; hydroxy-oxaalkyl containing 3-15 \carbon atoms,forexample- 2-hydroxy-3-(2,3-dihydroxypropoxy) propyl, 2-hydroxy-3-(Z-hydroxyethoxy) -propyl and 2 hydroxy 3[2-(2-hydroxyethoxy)'ethoxy]propyl; carboxy-lower alkyl containing 2-6carbon 'ato rns for example icarbox ymethyl and Z-carboxyethyl;cyano-lower alkyl containing 3-6 carbon atoms, for example 2-cyano-Patented Apr. 18, 1961 ice ' benzyl, 2,4-dichlorobenzyl, andmeta-bromobenzyl, lower alkylbenzyl such as ortho-methylbenzyl andpara-isopropylbenzyl, and lower alkoxy-benzyl such as p methoxybenzyland 3,4-diethoxybenzyl, as well as 2-chloro-4- methoxybenzyl,3-methoxy-4-rnethylbenzyl, 2-methoxy-4- chloroben'zyl, and the like; atleast one of the radicals Y vand Y being other than hydrogen. Ingeneral, the

compounds of Formula 1 above are high-melting yellow or green-yellowsolids which are substantially insoluble inwater. v .5

It is an'object of the instant invention to provide novel andimprovedmeans for facilitating the uniform dispersal of relatively smallproportions by weight of the waterinsoluble benzimidazolylstilbenewhitening and brightening agents of Formula I above'in aqueous mediacontaining Water-soluble synthetic organic anionic detergents. A

further object of this invention is the provision of .thesebenzimidazolylstilbenes in asolid composition which can be uniformlydispersed, either as a comminuted solid or in melted, liquid form, inaqueous pastes of water-soluble synthetic organic {anionic detergents toproduce detergents compositions providing the full dye strength of thebenzimidazolylstilbene when used in laundering.

In accordance with thepresent invention, a substantially water-insolublebenzimidazolylstilbene whitening and brightening agent of Formula Iabove is dissloved in an amide 'of the class consisting of higher fattyacid amides and higher fatty acid (lower alkanol)amides at atemperaturein the approximate range 140-200 C., thereby forming acomposition adapted to facilitate the preparation of'detergentcompositions containing a uniform dispersion of a relatively smallquantity of the benzimidazolylstilbene in a relatively large quantity ofan aqueous paste of'a water-soluble synthetic organic anionic detergent,that is, detergent compositions having up to about 0.5% by weight of thebenzimidazolylstilbene dispersed therein. Using any suitable means ofstirring or blending, an appropriate amount of a solution of thebenzimidazolylstilbene in the amide obtained in this manner can be addedwhile in hot, liquid form to the detergent-paste or, if desired, allowedto solidify by cool-.

ing and then added at anyconvenient time in re-melted,-

paste; In the detergent com-' the benzomidazolylstilbene;

whitenin g'and brightening agent is-dispersed uniformly liquid form tothe detergent positions thus prepared,

and satisfactorily, as evidenced by th'e fact that the dyeing strengthof the detergent compositions is approximately of the calculated amountbased onthe weight of the benzimidazolylstilbene employed, as determinedstandard dye testing procedures.

.The higher fatty acid amides useful in the practice of this inventionare'saturated aliphatic carboxylic primary amides'of the general formulaR- CO--'NH where R is an alkyl radical having about 8-18" carbon atoms.These amides are ofcourse well-known andreadily available compounds,being readily derived, for example, from the conespondinghigher fattyacids obtained by the; hydrolysis of various naturalfats' and oils suchas" coconut" oil and tallow. The corresponding higher fatty acid (lower-a1kanol)amides, having 8-18 carbon atoms, in the? ,aliphatic' chain,are likewise well-known and are readily prepared-byamidation ofthecorresponding higher fatty; acids or a suitable functional derivativethereof with a (monoor cli-lower'alkanoDarnine such as ethanolamine,

diethanolamine, isopropanolamine, and the like. Among the-preferredhigher fatty-acid amides and higher fatty aesaeas acid (loweralkanol)amides are: coconut fatty acid amides; coconut fatty acid (loweralkanol)amides such as coconut fatty acid ethanolamides and coconutfatty acid isopropanolamides; lauramide; lauric ethanolamide; lauricdiethanolamide; stearamide; stearic ethanolamide; palmitic acid amide;palmitic acid ethanolamide; and the like. These amides and (lowera1kanol)amides, in addition to functioning as a solvent for thebrightening agent, can also function as a foam stabilizer, but of courseother foam stabilizer substances can also be present in the detergent asknown in the art.

The water-soluble synthetic organic anionic detergents involved in thepractice of my invention are a Well-known class of substances (forexample,.see McCutcheons Syn thetic Detergents, McNair-Dorland Company,New York, 1950, pages 120-151) and include ordinary soaps (i.e., thealkaline metal salts of higher fatty acids), sulfonates, and sulfates.Examples of these detergents are alkyl aryl sulfonates, highervalkylsulfates, sulfated and sulfonated amides and amines, sulfated andsulfonated esters and others, and higher alkyl sulfonates, for instancesodium p-dodecylbenzenesulfonate, sodium lauryl sulfate, the sodium saltof Nemethyl-N- (2-sulfoethyl) oleic amide, the sodium salt of2-sulfoethyl oleate, and sodium myristyl' sulfonate. These detergentsare of course frequently available in admixture with each other or withinorganic detergents or builders such as tetra sodium pyrophosphate,sodium tripolyphosphate, sodium metasilicate, so dium borate, and sodiumperborate, or foam stabilizers such as lauric acid isopropanolamide andcoconut fatty acid ethanolamides. These mixtures are also satisfactoryfor the present purposes.

In carrying out my invention, the amount of benzimid-. azolylstilbeneWhich is dissolved in the amide can be varied as desired up to thesaturation concentration involved in each instance. As indicatedhereinabove the concentration of the benzimidazolylstilbene required inthe anionic detergent paste for the desired whitening and brighteningeffect isrelativel-y low, ordinarily being no more than 0.5% by weightand inmost instances falling in the range (Mil-01% by weight.Accordingly, it is feasible to use dilute solutions of thebenzimidazolylstilbene in the amide. However, i have found thatsolutions having about 5% or more by weight of thebenzirnidazolylstilbene have greater general usefulness than the moredilutesolutions, since the latter are less convenient to handle, due toincreased volume, and may in some instances involve introduction of alarger quantity of amide than desired into the anionic detergent.'Formost purposes, a concentration of 5-30 %-by weight of thebenzimidazolylstilbene in the amide solution is convenient andsatisfactory; using solutions of such concentration, the amount of theamide introduced into the'detergent paste is minimized and in fact. needbe no greater than'the amount in which amides of this type areconventionally used in anionic detergents to improve detergencyfi 7- Asalready indicated, the practical operative temperature range indissolving the benzimidazolylstilbene in the amideis about 140-200C.For-preparation of'relatively concentrated solutions, for instance 20%or'more', by, weight of.thebenzimidazolylstilbone, it is generallypreferable for best results to employ a temperature in .the'upperportiou of the operative range, for instance 180- 200-:C. In thepreparation ofless concentrated solu- 4 5-15 in the amide is cooled asrapidly as possible to solidify it quickly, and if necessary theresulting solid is comminuted in suitable fashion, as by grinding.

In carrying out this procedure, I generally prefer to cool the hotliquid solution of the benzimidazolylstilbene in the amide rapidly andefficiently by spraying it into a reservoir, or alternatively by pouringit onto the chilled rolls of a flaker so that thin brittle flakes of thedesired solid are produced. The solid product obtained by these methodscan be dispersed directly by conventional techniques into an aqueouspaste of a Water-soluble synthetic organic anionic detergent to producea detergent composition having a dyeing strength which is substantially100% of the calculated strength based on the amount ofbenzimidazolylstilbene present.

If the hot liquid solution of the benzimidazolylstilbene in the amide isnot cooled rapidly enough, use of .the solid form will result in adetergent composition having less than 100% of the calculated dyeingstrength, but theresulting solid can be used quite satisfactorily inre-melted, liquid form for addition to the detergent paste.

My invention is illustrated by the following examples without, however,being limited thereto. In these ex 7 amples, the term partf and .partsare used to indicate part or parts by weight. V

Example 1 q A general procedure is as follows:

One part of a benzimidazolylstilbene having Formula I hereinabove ismixed with nine parts of a mixture of coconut fatty acid amides havingthe formula H i where R represents the higher fattyaliphatic radicalstions, any temperature in the range -200 C. is

satisfactory for optimum results. r i

A particularly advantageous aspect of my invention is that item beemployed to provide'compositions con"- taining thebenzimidazolylstilbeneand .thejamide" in -.a conveniently handled, comminutedsolid'forrn-Which canbe readily and uniformlydispersed in aqueous pastesof water-soluble synthetic organic anionicdetergents. For such purpose,.a hot liquid solution containing up to about 20% by weight of thebenzimidazolylstilbene, f preferably. f

corresponding to those in the coconut fatty acids, RCOOH, and themixture is heated to C. After all the solid has dissolved, theresulting'solution is'stirred well while being heated at 150-160 C. andthen using preheated nitrogen is sprayed into a reservoir at roomtemperature (about 25 C.) to cool the liquid rapidly and solidify it.The resulting solid contains 10% by' weight of thebenzimidazolylstilbene.

Using the same general procedure, but melting the mixtures together ineach instance at C., there are employed appropriate amounts of thebenzimidazolylstilbene and the mixture of coconut oil fatty acid amidesto pro-, duce dry comminuted preparations containing 20% and 33%,respectively, of'thebenzimidazolylstilbene.

Appropriate amount-s of the 10%, 20%, and-33%- .were employed inaccordance with the above described produces: 4-(benzimidazol-2-yl)-4'-{1-[2-hydroxy-3-(2,3.- dihydroxypropoxy] propylbenzimidazol 2yl}stilbene,- 4-

(benzimidazol -;2 yl) 4' (1 4 allylbenzimidazol 2-,

yl) stilbene, and the mixture of hydroxyethylated deriva tives of4-(benzimida'zol-2-yl)-4'-{1-[2-hydroXy-3-(2,3-dihydroxypropoxy]propylbenzimidazol2 yl}stilbene described 'in Example 28E of;U.S. Patent 2,838,504. :Thewater-soluble synthetic organic ,ani onic, detergents ,.em;-

ployed in preparing these compositions were: -(1) De-.-'

tergent 'Lfconsisting of 21.8% of a mixture of-sodium lauryl sulfate and.-.sodium dodecylbenzenesulfonates; 18.2% of sodium sulfate, and 60% ofsodiumytriphos-n vphate; (2) Detergent H, consisting of 19.1% of sodiumI dodecylbenzenesulfqnates, 15.6% of sodium sulfate, 55 of sodiumtriphosphate, and 10.3% of sodium zcarbona-tei' and (3) whitesoapconsisting of the sodium salts of "the C rcmfatty acids derived from.tallow.' In each .,:of-the detergent compositions thus obtained, .I ewhitening:

Example: 2

Using the manipulative procedures described above in Example 1, twoseries of-detergent compositions were prepared in which equal weights,respectively, of coconut fatty acid ethanolamides-and coconut fatty acidisopropanolamides were substituted for the coconut fatty acid amidesused in Example 1. In the two series of detergent compositions thusobtained, in each instance the whitening and brightening efiect of thecomposition was 100% of the calculated amount, based on the weight ofthe benzimidazolylstilbene employed.

Example 3 The procedures described in Example 1 were repeated for thepreparation of the solutions of the benzirnidazolylstilbenes in theamide with the exception that the hot liquid solution was cooled bypouring it into a steel tray which rested on a polyethylene bag filledwith chipped ice. The dyeing strength of the detergent compositionsprepared from the solidified product by dispersing the ground solidproduct in the aqueous detergent paste were in each instanceapproximately 85% of the strength calculated on the basis of the weightof the benzimidazolylstilbene employed. On the other hand, when theground solidproduct, instead of being added as such to the detergentpaste, was re-melted by heating it to 100-110" C. and the resulting hotliquid was mixed with a hot (76 C.) aqueous detergent paste, thedetergent compositions thus obtainedhad a dyeing strength which was 100%of the calculated amount. 7

In the manipulative procedures of the foregoing examples, there can beused, as the whitening and brightening agent, the following:4-(benzimidaZol-2-yl)'-4-(lmethylbenzimidazol-Z-yl) stilbene; 4,4-bis l-(Z-hydroxyethyl) benzimidazol-Z-yl] stilbene; 4-(benzimidazol-2-yl) 4 [1(2 hydroxy 2 sulfopropyl)benzimidaz0l-2-yl]- stilbene; 4'-[ l-(carboxymethyl)benzimidazQlQ-ylb t?(;1- methylbenzimidazol-Z-yl)stilbene; I ftAf-bis l- 2-cyanoethyl) benzimida'zol-2-yl) stilbene;4-(benzimidazol-2-yl) -4-7 l-allylbenzimidazol-2-yl) stilbene; and4,4'-bis l-(orthochlorobenzyl)benzimidazol 2 yl]stilbene. In eachinstance, the resulting detergent compositions obtained have a dyeingstrength which is approximately 100% of the calculated amount based onthe weight of the benzimidazolylstilbene employed.

I claim:

1. The process for obtaining a uniform dispersion of a relatively smallquantity of a benzimidazolylstilbene whitening and brightening agenthaving the formula g wherein Y and Y are radicals of the classconsisting of 4 hydrogen,-lower alkyl containing l-6 carbonatoms, hy-

droxy lower alkyl containing 2-6 carbon atoms, 2-hy- 6'5 C. inacoconutfatty acid ethanolamide; and mixing the resulting solutionwiththe said aqueous paste in the pro-- portionof 0.0l.-0.5 part by weightof'thebenzimidazolylstilbene per hundred parts by weight of the aqueouspaste.

droxy-3 -sulfopropyl, hydroxy-oxaalkyl containing 3-15 carbon atoms,carboxy-lower alkyl containing 2-6 carbon atoms, cyano-lower alkylcontaining 3-6 carbon atoms, allyl, methallyl, and monocyclic aralkylcontaining 7-11 carbon atoms, at least one of the radicals Y and Y beingother than hydrogen, in a relatively large quantity of an aqueous pasteof a water-soluble synthetic organic anionic detergent which comprises:dissolving the benzimidazolylstilbene at a temperature inthe range -200C. in an amide of the class consisting of higher fatty acid amides and.higher fatty acid lower alkanol amides; and mixing the resultingsolution with the said aqueous paste in'the proportion of 0;0l-0.5 partby weight of the benzimidazolylstilbene per, hundred parts by weight ofthe aqueouspaste. r

2. The process in accordance with claim 1 wherein Y is hydrogen and Yis, a hydroxy-oxaalkyl radical containing 3-15 carbon atoms, and theamide is a higherfatty acid amide.

3. The process in accordance with claim 1 wherein Y is hydrogen and Y isa hydroxy-oxaalkyl radical containing 3-15 carbon atoms, and the amideis a higher fatty acid lower alkanolamide,

4. The process in accordance with claim 1 wherein Y 5. The process in,accordance with claim 1 whereinY is a hydroxy-lower alkyl radicalcontaining 2-6 carbon atoms and Y is a hydroxy oxaalkyl 'radi'calcontaining 3-15 carbon atoms, and the amide is lahigher fatty loweralkanolamide.

' 6. The process for obtaining a dispersion'of a relati'vely smallquantity of abenzimidazolylstilbene whitening brightening agent havingthe formula where Y is a hydroxy-oxaalkyl radical containing 3-15 carbonatoms, in'arelatively large quantity of an aqueous pasteof awater-soluble syntlie'ticorganic anionic sulfonate detergent whichcomprises: dissolvingthe benzimidazolylstilbene at a temperature in therange 140-200 v7. The process for obtaining a uniform dispersion of arelatively small 'quantity of a benzimidazolylstilbene whiteningbrightening agent having the formula Y aaaa aaa ture in the approximaterange 140-200 C. a water-insoluble benzimidazolylstilbene whitening andbrightening agent having the formula wherein'Y and Y are radicals of theclass consisting of" hydrogen, lower alkyl containing 1-6 carbonatoms,thy-

droxy-lower alkyl containing 2-6 carbon atoms, ,2-hydroXy-3-sulfopropyl,hydroxy-oxaalkyl containing 3-15' carbon atoms, carboxy-lower alkylcontaining 2-6' carbon atoms, cyano-lower alkyl containing 3-6 carbonatoms, allyl,]methallyl, and monocyclicf aralkyl containing 7-11 carbonatoms, at least one of the radicals Y and Y being other thanhydrogen, inan amide of the class consisting of higher fatty acid amides and higherfatty acid lower alkanolarnides.

9. A solid composition obtained by dissolving at a temperature in theapproximate range 140-200 C. about 15% by weight of abenzimidazolylstilbene whitening and brightening agent having theformula wherein Y and Y are radicals of the class consisting ofhydrogen, lower alkyl containing 1-6 carbon atoms, hydroxy-lower alkylcontaining 2-6--carbon atoms, 2-hy-' droxy-S-sulfopropyl,hydroxy-oxaalkyl containing 3-715- carbon atoms, carboxy-lower alkylcontaining2-6 carbon atoms, cyano-low er alkyl containing 3-6carbonatoms, allyl, niethallyl, and monocyclic aralkyl containing 7-11carbon atoms, at least one of the radicals Y and Y being other thanhydrogen, in an amide of the class consisting of higher fatty acidamides and higher fatty acid lower alkanolamides, and solidifying theresulting solution by cooling it rapidly. 7 r

"10. A solid composition obtained by dissolving at a temperature in theapproximate range -200 C. about 5-15% by weight of 'abenzimidazolyl'stilbene whitening and'brightening agent having theformula where Y is a hydroxy-lower alkyl radical containing 2-6 carbonatoms and Y is a hydroxy-oxaalkyl radical containing 3-15 carbon atoms,in a coconut fatty acid ethanolamide, and solidifying the resultingsolution by cooling it rapidly.

References t'lited in the file, of this patent UNITED STATES PATENTS2,607,740 Vitale etal -Aug. 19, 1952 2,733,214 Vitale et a1. "Jan. 31,1956 2,838,504 vCrounse June 10, 1958 OTHER REFERENCES 'Reinisch et al.:Fatty Acid Alkylolamides, pages 169-178 in Jour. Soc. of CosmeticChemists, 01. s, No.

3, November 4.

1. THE PROCESS FOR OBTAINING A UNIFORM DISPERSION OF A RELATIVELY SMALLQUANTITY OF A BENZIMIDAZOLYLSTILBENE WHITENING AND BRIGHTENING AGENTHAVING THE FORMULA